The invention relates to optical fiber terminations, and in particular to a termination which provides an output of a light beam in a direction traverse to the direction of the beam propagation.
Existing optical fiber terminations are designed so as to reduce backward reflections of light into the fiber and/or to provide optimal coupling between two co-axial fibers. These functions are rather limited and do not solve a problem that has arisen recently because of the constant demand of reducing the size of optoelectronic components and increasing the density of optoelectronic packaging. The problem is concerned with utilizing a three dimensional space in a package more efficiently while using optoelectronic components of a smaller size. For example, it is preferred to mount semiconductor devices such as detectors parallel to the package base with the active area facing up. Also it is preferred to pass optical feedthrough fibers through the package sidewalls. Accordingly, it generates a requirement for the fiber to provide an output of the laser light in a flexible manner while ensuring enhanced functionality of the fiber and the use of minimal optical elements. Discrete optical components are costly-and difficult to align and therefore should be avoided. Additional requirements for the fiber or fiber termination of this kind would be simple design and manufacturing along with an easy alignment with other elements in a package.
None of the existing fiber terminations have addressed the above-mentioned problems so far.
It is therefore an object of the invention to provide an optical fiber termination which would provide enhanced functionality of the fiber while providing output of laser light in a flexible manner.
According to one aspect of the invention there is provided an optical fiber having an optical element formed at an end of the fiber,
the element providing an output of a light beam, propagating through the fiber, in a direction traverse to the direction of the beam propagation while reshaping the beam into a spot of a required shape and size,
the element being an integral part of the fiber.
Conveniently, the optical element is an angled ball, the angle of the angled surface of which is chosen so as to provide a total internal reflection of the beam. Depending on the requirements for the fiber, the diameter of the ball may be either substantially equal the diameter of the fiber or greater than the diameter of the fiber at a joint with the ball. Alternatively, the optical element may comprise an angled fiber end and a lens, the lens being disposed so as to receive the beam reflected from the angled fiber end. The lens may be replaced with a cylindrical or tapered multimode fiber section having a lens at its lens, or any other optical element which would provide a similar function. Conveniently, the fiber comprises a groove for receiving the lens.
Conveniently, the optical element provides the output of the light beam in a direction substantially perpendicular or perpendicular to the direction of the beam propagation within the fiber. Alternatively, it may provide output of the light beam in a direction forming an acute angle or obtuse angle with the direction of the beam propagation.
According to another aspect of the invention there is provided an optical fiber termination, comprising an optical element formed at one end thereof,
the element being designed so that, when the termination is being coupled to a fiber, to provide an output of a light beam, propagating through the fiber, in a direction traverse to the direction of the beam propagation while reshaping the beam into a spot of a required shape and size,
the element being an integral part of the termination.
Conveniently, the optical element is an angled ball, the angle of the angled surface of which is chosen so as to provide a total internal reflection of the beam. The diameter of the ball may be substantially equal the diameter of the fiber or greater than the diameter of the fiber at a joint with the ball depending on the requirement for the fiber termination. Alternatively, the optical element of the termination may be formed by an angled fiber end and a lens, the lens being disposed so as to receive the beam reflected from the angled fiber end. In other embodiments of the invention the lens is replaced with a cylindrical or tapered multimode section, having a lens at the end of the taper, which a provide similar function.
Conveniently, the termination provides the output of the light beam in a direction perpendicular or substantially perpendicular to the direction of the beam propagation. Alternatively, the termination may provide output of the light beam in a direction forming an acute or obtuse angle with the direction of the beam propagation. Additionally, an assembly of an optical fiber and the termination described above is provided, thus forming a combined optical fiber, wherein the other end of the termination is appended, e.g. spliced, to the optical fiber.